Radio link monitoring without always-on reference signals

ABSTRACT

Methods, systems, and devices for wireless communication are described. A discontinuous reception (DRX) periodicity may be configured to enable monitoring of a reference signal (RS) for RLM procedures. For example, a transmitting device may configure a DRX periodicity for an RS, where the configured DRX periodicity may include a periodicity of discrete transmissions of the RS or a periodicity of a transmission window in which the RS is located. Accordingly, a receiving device may identify the DRX periodicity and monitor radio link quality using the RS based on the DRX periodicity. In some examples, the RS may be transmitted independent of control channel transmissions, and the transmitting device may configure one or more control resource sets for the RS.

CROSS REFERENCES AND PRIORITY CLAIM

The present Application for Patent claims priority to U.S. ProvisionalPatent Application Ser. No. 62/470,862 by Lee et al., entitled “RadioLink Monitoring Without Always-On Reference Signals,” filed Mar. 13,2017, which is assigned to the assignee hereof and is herebyincorporated by reference in its entirety.

INTRODUCTION

The following relates generally to wireless communication, and morespecifically to radio link monitoring (RLM) without always-on referencesignals (RSs). Certain embodiments enable and provide communicationdevices, methods, systems, and techniques with improved connectionreliability and power efficient usage.

Wireless communications systems are widely deployed to provide varioustypes of communication content such as voice, video, packet data,messaging, broadcast, and so on. These systems may be capable ofsupporting communication with multiple users by sharing the availablesystem resources (e.g., time, frequency, and power). Examples of suchmultiple-access systems include code division multiple access (CDMA)systems, time division multiple access (TDMA) systems, frequencydivision multiple access (FDMA) systems, and orthogonal frequencydivision multiple access (OFDMA) systems, (e.g., a Long Term Evolution(LTE) system, or a New Radio (NR) system). A wireless multiple-accesscommunications system may include a number of base stations or accessnetwork nodes, each simultaneously supporting communication for multiplecommunication devices, which may be otherwise known as user equipment(UE).

Receiving devices (e.g., UEs) in some wireless communications systemsmay monitor radio link quality to determine synchronicity whencommunicating with a transmitting device (e.g., a base station, anotherUE, etc.) and identify radio link failures. In such cases, the receivingdevice may use a quality of an always-on transmission of certain RSs toperform radio link quality measurements. However, some systems may notuse always-on transmissions of these RSs, and efficient techniques forradio link monitoring may be desirable to ensure robust communications.

SUMMARY

The described techniques relate to improved methods, systems, devices,or apparatuses that support RLM without always-on RSs. Generally, thedescribed techniques provide for the use of a discontinuous reception(DRX) periodicity to enable monitoring of an RS used for RLM proceduresassociated with a downlink control channel. For example, a transmittingdevice (e.g., a base station) may configure a DRX periodicity for an RS,where the configured DRX periodicity may include a periodicity ofdiscrete transmissions of the RS or a periodicity of a transmissionwindow in which the RS is located (e.g., within at least onetransmission time interval (TTI) of respective transmission windows).Accordingly, a receiving device (e.g., a UE) may identify the DRXperiodicity and monitor radio link quality using the RS based on the DRXperiodicity. In some examples, the RS may be transmitted independent ofcontrol channel transmissions, and the transmitting device may configureone or more control resource sets for the RS. Additionally, thereceiving device may opportunistically monitor radio link qualityindependent of the configured DRX periodicity associated with the RS(e.g., the receiving device may monitor radio link quality outside ofthe configured discrete transmissions or transmission windows).

A method of wireless communication is described. The method may includeidentifying a DRX periodicity for an RS for RLM procedures, monitoring,based at least in part on the identified DRX periodicity of the RS, aradio link quality, and receiving the RS according to the DRXperiodicity.

An apparatus for wireless communication is described. The apparatus mayinclude means for identifying a DRX periodicity for an RS for RLMprocedures, means for monitoring, based at least in part on theidentified DRX periodicity of the RS, a radio link quality, and meansfor receiving the RS according to the DRX periodicity.

Another apparatus for wireless communication is described. The apparatusmay include a processor, memory in electronic communication with theprocessor, and instructions stored in the memory. The instructions maybe operable to cause the processor to identify a DRX periodicity for anRS for RLM procedures, monitor, based at least in part on the identifiedDRX periodicity of the RS, a radio link quality, and receive the RSaccording to the DRX periodicity.

A non-transitory computer-readable medium for wireless communication isdescribed. The non-transitory computer-readable medium may includeinstructions operable to cause a processor to identify a DRX periodicityfor an RS for RLM procedures, monitor, based at least in part on theidentified DRX periodicity of the RS, a radio link quality, and receivethe RS according to the DRX periodicity.

Some examples of the method, apparatus, and non-transitorycomputer-readable medium described above may further include processes,features, means, or instructions for determining a periodicity ofdiscrete transmissions of the RS. Some examples of the method,apparatus, and non-transitory computer-readable medium described abovemay further include processes, features, means, or instructions formonitoring the radio link quality independent of the periodicity of thediscrete transmissions of the RS based at least in part on a detectedpresence of the RS.

Some examples of the method, apparatus, and non-transitorycomputer-readable medium described above may further include processes,features, means, or instructions for determining a periodicity oftransmission windows for the RS, wherein the RS may be received withinrespective transmission windows, and monitoring the radio link qualityindependent of the periodicity of the transmission windows based atleast in part on a detected presence of the RS.

In some examples of the method, apparatus, and non-transitorycomputer-readable medium described above, each of the respectivetransmission windows comprises one or more TTIs, and the RS may beincluded within at least one TTI of the one or more TTIs. Some examplesof the method, apparatus, and non-transitory computer-readable mediumdescribed above may further include processes, features, means, orinstructions for receiving an indication of the DRX periodicity or of alength of the respective transmission windows, wherein the indicationmay be received via radio resource control (RRC) signaling, systeminformation broadcast signaling, or a combination thereof.

Some examples of the method, apparatus, and non-transitorycomputer-readable medium described above may further include processes,features, means, or instructions for selecting the RS within aparticular transmission window for the RLM procedures based at least inpart on one or more signal-to-noise ratios (SNRs) of discretetransmissions of the RS within the respective transmission windows.

Some examples of the method, apparatus, and non-transitorycomputer-readable medium described above may further include processes,features, means, or instructions for selecting the RS within aparticular TTI for the RLM procedures based at least in part on one ormore SNRs of discrete transmissions of the RS within one or more TTIswithin the respective transmission windows. In some examples of themethod, apparatus, and non-transitory computer-readable medium describedabove, the DRX periodicity for the RS may be independent of reception ofcontrol channels.

Some examples of the method, apparatus, and non-transitorycomputer-readable medium described above may further include processes,features, means, or instructions for identifying one or more controlresource sets associated with receiving the RS associated with the RLMprocedures. In some examples of the method, apparatus, andnon-transitory computer-readable medium described above, the one or morecontrol resource sets comprise at least resources associated with acommon control channel or resources associated with a UE-specificcontrol channel.

Some examples of the method, apparatus, and non-transitorycomputer-readable medium described above may further include processes,features, means, or instructions for identifying a first controlresource set associated with receiving the RS. Some examples of themethod, apparatus, and non-transitory computer-readable medium describedabove may further include processes, features, means, or instructionsfor identifying a second control resource set associated with receivingthe RS. Some examples of the method, apparatus, and non-transitorycomputer-readable medium described above may further include processes,features, means, or instructions for using at least the first controlresource set, the second control resource set, or a combination thereofthe RLM procedures.

Some examples of the method, apparatus, and non-transitorycomputer-readable medium described above may further include processes,features, means, or instructions for decoding the downlink controlchannel. Some examples of the method, apparatus, and non-transitorycomputer-readable medium described above may further include processes,features, means, or instructions for resetting or boosting an RLMcounter based at least in part on the decoded downlink control channel.

In some examples of the method, apparatus, and non-transitorycomputer-readable medium described above, boosting the RLM countercomprises: identifying a type of control channel resources or anaggregation level associated with the downlink control channel. Someexamples of the method, apparatus, and non-transitory computer-readablemedium described above may further include processes, features, means,or instructions for boosting the RLM counter based at least in part onthe identified type of control channel resources or aggregation level.

A method of wireless communication is described. The method may includeidentifying an RS for RLM procedures, configuring a DRX periodicity forthe RS, and transmitting the RS according to the configured DRXperiodicity.

An apparatus for wireless communication is described. The apparatus mayinclude means for identifying an RS for RLM procedures, means forconfiguring a DRX periodicity for the RS, and means for transmitting theRS according to the configured DRX periodicity.

Another apparatus for wireless communication is described. The apparatusmay include a processor, memory in electronic communication with theprocessor, and instructions stored in the memory. The instructions maybe operable to cause the processor to identify an RS for RLM procedures,configure a DRX periodicity for the RS, and transmit the RS according tothe configured DRX periodicity.

A non-transitory computer-readable medium for wireless communication isdescribed. The non-transitory computer-readable medium may includeinstructions operable to cause a processor to identify an RS for RLMprocedures, configure a DRX periodicity for the RS, and transmit the RSaccording to the configured DRX periodicity.

Some examples of the method, apparatus, and non-transitorycomputer-readable medium described above may further include processes,features, means, or instructions for configuring a periodicity oftransmission windows for the RS wherein the RS may be transmitted withinrespective transmission windows, or configuring a periodicity ofdiscrete transmissions of the RS. In some examples of the method,apparatus, and non-transitory computer-readable medium described above,each of the respective transmission windows comprises one or more TTIs,and the RS may be transmitted within at least one TTI of the one or moreTTIs.

Some examples of the method, apparatus, and non-transitorycomputer-readable medium described above may further include processes,features, means, or instructions for transmitting an indication of theDRX periodicity or of a length of the respective transmission windows,wherein the indication may be transmitted via RRC signaling, systeminformation broadcast signaling, or a combination thereof. In someexamples of the method, apparatus, and non-transitory computer-readablemedium described above, the DRX periodicity for the RS may beindependent of control channel transmissions.

Some examples of the method, apparatus, and non-transitorycomputer-readable medium described above may further include processes,features, means, or instructions for configuring one or more controlresource sets for transmission of the RS associated with the RLMprocedures. In some examples of the method, apparatus, andnon-transitory computer-readable medium described above, the one or morecontrol resource sets comprise at least resources associated with acommon control channel or resources associated with a UE-specificcontrol channel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a system for wireless communicationthat supports RLM without always-on RSs in accordance with aspects ofthe present disclosure.

FIG. 2 illustrates an example of a wireless communications system thatsupports RLM without always-on RSs in accordance with aspects of thepresent disclosure.

FIGS. 3 and 4 illustrate examples of DRX configurations that support RLMwithout always-on RSs in accordance with aspects of the presentdisclosure.

FIG. 5 illustrates an example of a process flow in a system thatsupports RLM without always-on RSs in accordance with aspects of thepresent disclosure.

FIGS. 6 through 8 show block diagrams of a device that supports RLMwithout always-on RSs in accordance with aspects of the presentdisclosure.

FIG. 9 illustrates a block diagram of a system including a UE thatsupports RLM without always-on RSs in accordance with aspects of thepresent disclosure.

FIGS. 10 through 12 show block diagrams of a device that supports RLMwithout always-on RSs in accordance with aspects of the presentdisclosure.

FIG. 13 illustrates a block diagram of a system including a base stationthat supports RLM without always-on RSs in accordance with aspects ofthe present disclosure.

FIGS. 14 through 19 illustrate methods for RLM without always-on RSs inaccordance with aspects of the present disclosure.

DETAILED DESCRIPTION

User equipments (UEs) may monitor downlink radio link quality todetermine whether radio link failures occur. For example, in somewireless communications systems, a UE may use a hypothetical controlchannel block error rate (BLER) (e.g., a BLER of a hypothetical physicaldownlink control channel (PDCCH)) based on a quality of an always-oncell-specific reference signal (CRS) for radio link monitoring (RLM).However, some systems may not employ a regular or always-on transmissionof CRS.

As described herein, RLM procedures within some wireless communicationssystems may utilize a configured (e.g., a guaranteed) periodicity of areference signal (RS) associated with downlink control channels (e.g., aphysical downlink control channel (PDCCH), an enhanced PDCCH (ePDCCH),and the like). For example, a receiving device (e.g., a UE) may monitorradio link quality at certain intervals based on a discontinuousreception (DRX) periodicity associated with an RS. In such cases, theDRX periodicity may include a discrete periodicity of transmissions ofthe RS, or may include a periodicity of a transmission window thatincludes the RS. Accordingly, through the use of the configured RS, areceiving device may perform RLM in the absence of always-on RSs.

In some cases, the transmission of the RS may be independent of controlchannel transmissions. Additionally, the receiving device mayopportunistically monitor downlink radio link quality outside of theconfigured occasions when the receiving device detects a presence of theRS. The RS may also be associated with certain control channel resourcesets. For example, the RS may be associated with common controlchannels, UE-specific control channels, or both. Accordingly, areceiving device may use different control channel resource sets for RLMprocedures using the RS.

Aspects of the disclosure are initially described in the context of awireless communications system. Examples are also provided thatillustrate DRX periodicity used for monitoring radio link quality.Aspects of the disclosure are further illustrated by and described withreference to apparatus diagrams, system diagrams, and flowcharts thatrelate to RLM without always-on RSs.

While aspects and embodiments are described in this application withreference to certain examples, those skilled in the art will understandthat additional implementations and use cases may come about in manydifferent arrangements and scenarios. Innovations described herein maybe implemented across many differing platform types, devices, systems,shapes, sizes, and packaging arrangements. For example, embodimentsand/or uses may come about via integrated chip embodiments and othernon-module-component based devices (e.g., end-user devices, vehicles,communication devices, computing devices, industrial equipment,retail/purchasing devices, medical devices, AI-enabled devices, etc.).While some examples may or may not be specifically directed to use casesor applications, a wide assortment of applicability of describedinnovations may occur. Implementations may range from chip-level ormodular components to non-modular, non-chip-level implementations,and/or to aggregate, distributed, or OEM devices or systemsincorporating one or more aspects of the described innovations. In somepractical settings, devices incorporating described aspects and featuresmay also necessarily include additional components and features for theimplementation and practice of claimed and described embodiments. Forexample, transmission and reception of wireless signals necessarilyincludes a number of components for analog and digital purposes (e.g.,hardware components including one or more antennas, RF-chains, poweramplifiers, modulators, buffers, processors, interleavers,adders/summers, etc.). It is intended that innovations described hereinmay be practiced in a wide variety of devices, chip-level components,systems, distributed arrangements, end-user devices, etc. of varyingsizes, shapes, and constitution.

FIG. 1 illustrates an example of a wireless communications system 100 inaccordance with various aspects of the present disclosure. The wirelesscommunications system 100 includes base stations 105, UEs 115, and acore network 130. In some examples, the wireless communications system100 may be a Long Term Evolution (LTE), an LTE-Advanced (LTE-A) network,or a New Radio (NR) network. In some cases, wireless communicationssystem 100 may support enhanced broadband communications, ultra-reliable(i.e., mission critical) communications, low latency communications, andcommunications with low-cost and low-complexity devices. Wirelesscommunications system 100 may support the use of configured DRXperiodicities to enable efficient RLM procedures that do not rely on analways-on RS.

Base stations 105 may wirelessly communicate with UEs 115 via one ormore base station antennas. Each base station 105 may providecommunication coverage for a respective geographic coverage area 110.Communication links 125 shown in wireless communications system 100 mayinclude uplink transmissions from a UE 115 to a base station 105, ordownlink transmissions, from a base station 105 to a UE 115. Controlinformation and data may be multiplexed on an uplink channel or downlinkaccording to various techniques. Control information and data may bemultiplexed on a downlink channel, for example, using time divisionmultiplexing (TDM) techniques, frequency division multiplexing (FDM)techniques, or hybrid TDM-FDM techniques. In some examples, the controlinformation transmitted during a transmission time interval (TTI) of adownlink channel may be distributed between different control regions ina cascaded manner (e.g., between a common control region and one or moreUE-specific control regions).

UEs 115 may be dispersed throughout the wireless communications system100, and each UE 115 may be stationary or mobile. A UE 115 may also bereferred to as a mobile station, a subscriber station, a mobile unit, asubscriber unit, a wireless unit, a remote unit, a mobile device, awireless device, a wireless communications device, a remote device, amobile subscriber station, an access terminal, a mobile terminal, awireless terminal, a remote terminal, a handset, a user agent, a mobileclient, a client, or some other suitable terminology. A UE 115 may alsobe a cellular phone, a personal digital assistant (PDA), a wirelessmodem, a wireless communication device, a handheld device, a tabletcomputer, a laptop computer, a cordless phone, a personal electronicdevice, a handheld device, a personal computer, a wireless local loop(WLL) station, an Internet of Things (IoT) device, an Internet ofEverything (IoE) device, a machine type communication (MTC) device, anappliance, an automobile, or the like.

In some cases, a UE 115 may also be able to communicate directly withother UEs (e.g., using a peer-to-peer (P2P) or device-to-device (D2D)protocol). One or more of a group of UEs 115 utilizing D2Dcommunications may be within the coverage area 110 of a cell. Other UEs115 in such a group may be outside the coverage area 110 of a cell, orotherwise unable to receive transmissions from a base station 105. Insome cases, groups of UEs 115 communicating via D2D communications mayutilize a one-to-many (1:M) system in which each UE 115 transmits toevery other UE 115 in the group. In some cases, a base station 105facilitates the scheduling of resources for D2D communications. In othercases, D2D communications are carried out independent of a base station105.

Some UEs 115, such as MTC or IoT devices, may be low cost or lowcomplexity devices, and may provide for automated communication betweenmachines, i.e., Machine-to-Machine (M2M) communication. M2M or MTC mayrefer to data communication technologies that allow devices tocommunicate with one another or a base station without humanintervention. For example, M2M or MTC may refer to communications fromdevices that integrate sensors or meters to measure or captureinformation and relay that information to a central server orapplication program that can make use of the information or present theinformation to humans interacting with the program or application. SomeUEs 115 may be designed to collect information or enable automatedbehavior of machines. Examples of applications for MTC devices includesmart metering, inventory monitoring, water level monitoring, equipmentmonitoring, healthcare monitoring, wildlife monitoring, weather andgeological event monitoring, fleet management and tracking, remotesecurity sensing, physical access control, and transaction-basedbusiness charging.

In some cases, an MTC device may operate using half-duplex (one-way)communications at a reduced peak rate. MTC devices may also beconfigured to enter a power saving “deep sleep” mode when not engagingin active communications. In some cases, MTC or IoT devices may bedesigned to support mission critical functions and wirelesscommunications system may be configured to provide ultra-reliablecommunications for these functions.

Base stations 105 may communicate with the core network 130 and with oneanother. For example, base stations 105 may interface with the corenetwork 130 through backhaul links 132 (e.g., S1, etc.). Base stations105 may communicate with one another over backhaul links 134 (e.g., X2,etc.) either directly or indirectly (e.g., through core network 130).Base stations 105 may perform radio configuration and scheduling forcommunication with UEs 115, or may operate under the control of a basestation controller (not shown). In some examples, base stations 105 maybe macro cells, small cells, hot spots, or the like. Base stations 105may also be referred to as evolved NodeBs (eNBs) or gNodeBs (gNBs) 105.

The core network 130 may provide user authentication, accessauthorization, tracking, Internet Protocol (IP) connectivity, and otheraccess, routing, or mobility functions. At least some of the networkdevices, such as base station 105 may include subcomponents such as anaccess network entity, which may be an example of an access nodecontroller (ANC). Each access network entity may communicate with anumber of UEs 115 through a number of other access network transmissionentities, each of which may be an example of a smart radio head, or atransmission/reception point (TRP). In some configurations, variousfunctions of each access network entity or base station 105 may bedistributed across various network devices (e.g., radio heads and accessnetwork controllers) or consolidated into a single network device (e.g.,a base station 105).

Wireless communications system 100 may operate in an ultra-highfrequency (UHF) frequency region using frequency bands from 700megahertz (MHz) to 2600 MHz (2.6 gigahertz (GHz)), although somenetworks (e.g., a wireless local area network (WLAN)) may usefrequencies as high as 4 GHz. This region may also be known as thedecimeter band, since the wavelengths range from approximately onedecimeter to one meter in length. UHF waves may propagate mainly by lineof sight, and may be blocked by buildings and environmental features.However, the waves may penetrate walls sufficiently to provide serviceto UEs 115 located indoors. Transmission of UHF waves is characterizedby smaller antennas and shorter range (e.g., less than 100 kilometers(km)) compared to transmission using the smaller frequencies (and longerwaves) of the high frequency (HF) or very high frequency (VHF) portionof the spectrum. In some cases, wireless communications system 100 mayalso utilize extremely high frequency (EHF) portions of the spectrum(e.g., from 30 GHz to 300 GHz). This region may also be known as themillimeter band, since the wavelengths range from approximately onemillimeter to one centimeter in length. Thus, EHF antennas may be evensmaller and more closely spaced than UHF antennas. In some cases, thismay facilitate use of antenna arrays within a UE 115 (e.g., fordirectional beamforming). However, EHF transmissions may be subject toeven greater atmospheric attenuation and shorter range than UHFtransmissions.

Wireless communications system 100 may support beam formed or millimeterwave (mmW) communications between UEs 115 and base stations 105. Devicesoperating in mmW or EHF bands may have multiple antennas to allowbeamforming. That is, a base station 105 may use multiple antennas orantenna arrays to conduct beamforming operations for directionalcommunications with a UE 115. Beamforming (which may also be referred toas spatial filtering or directional transmission) is a signal processingtechnique that may be used at a transmitter (e.g., a base station 105)to shape and/or steer an overall antenna beam in the direction of atarget receiver (e.g., a UE 115). This may be achieved by combiningelements in an antenna array in such a way that transmitted signals atparticular angles experience constructive interference while othersexperience destructive interference.

Multiple-input multiple-output (MIMO) wireless systems use atransmission scheme between a transmitter (e.g., a base station 105) anda receiver (e.g., a UE 115), where both transmitter and receiver areequipped with multiple antennas. Some portions of wirelesscommunications system 100 may use beamforming. For example, base station105 may have an antenna array with a number of rows and columns ofantenna ports that the base station 105 may use for beamforming in itscommunication with UE 115. Signals may be transmitted multiple times indifferent directions (e.g., each transmission may be beamformeddifferently). A mmW receiver (e.g., a UE 115) may try multiple beams(e.g., antenna subarrays) while receiving the synchronization signals.

In some cases, the antennas of a base station 105 or UE 115 may belocated within one or more antenna arrays, which may support beamformingor MIMO operation. One or more base station antennas or antenna arraysmay be collocated at an antenna assembly, such as an antenna tower. Insome cases, antennas or antenna arrays associated with a base station105 may be located in diverse geographic locations. A base station 105may multiple use antennas or antenna arrays to conduct beamformingoperations for directional communications with a UE 115.

In some cases, wireless communications system 100 may be a packet-basednetwork that operate according to a layered protocol stack. In the userplane, communications at the bearer or Packet Data Convergence Protocol(PDCP) layer may be IP-based. A radio link control (RLC) layer may insome cases perform packet segmentation and reassembly to communicateover logical channels. A medium access control (MAC) layer may performpriority handling and multiplexing of logical channels into transportchannels. The MAC layer may also use hybrid automatic repeat request(HARM) to provide retransmission at the MAC layer to improve linkefficiency. In the control plane, the radio resource control (RRC)protocol layer may provide establishment, configuration, and maintenanceof an RRC connection between a UE 115 and a network device (e.g., a basestation 105), or core network 130 supporting radio bearers for userplane data. At the physical (PHY) layer, transport channels may bemapped to physical channels.

Time intervals in LTE or NR may be expressed in multiples of a basictime unit (which may be a sampling period of T_(s)=1/30,720,000seconds). Time resources may be organized according to radio frames oflength of 10 milliseconds (ms) (T_(f)=307200T_(s)), which may beidentified by a system frame number (SFN) ranging from 0 to 1023. Eachframe may include ten 1 ms subframes numbered from 0 to 9. A subframemay be further divided into two 0.5 ms slots, each of which contains 6or 7 modulation symbol periods (depending on the length of the cyclicprefix prepended to each symbol). Excluding the cyclic prefix, eachsymbol contains 2048 sample periods. In some cases the subframe may bethe smallest scheduling unit, also known as a TTI. In other cases, a TTImay be shorter than a subframe or may be dynamically selected (e.g., inshort TTI bursts or in selected component carriers using short TTIs).

A resource element may consist of one symbol period and one subcarrier(e.g., a 15 kilohertz (kHz) frequency range). A resource block maycontain 12 consecutive subcarriers in the frequency domain and, for anormal cyclic prefix in each orthogonal frequency division multiplexed(OFDM) symbol, 7 consecutive OFDM symbols in the time domain (1 slot),or 84 resource elements. The number of bits carried by each resourceelement may depend on the modulation scheme (the configuration ofsymbols that may be selected during each symbol period). Thus, the moreresource blocks that a UE 115 receives and the higher the modulationscheme, the higher the data rate may be.

Wireless communications system 100 may support operation on multiplecells or carriers, a feature which may be referred to as carrieraggregation (CA) or multi-carrier operation. A carrier may also bereferred to as a component carrier (CC), a layer, a channel, etc. Theterms “carrier,” “component carrier,” “cell,” and “channel” may be usedinterchangeably herein. A UE 115 may be configured with multipledownlink CCs and one or more uplink CCs for carrier aggregation. Carrieraggregation may be used with both frequency division duplexed (FDD) andtime division duplexed (TDD) component carriers.

In some cases, wireless communications system 100 may utilize enhancedcomponent carriers (eCCs). An eCC may be characterized by one or morefeatures including: wider bandwidth, shorter symbol duration, shorterTTIs, and modified control channel configuration. In some cases, an eCCmay be associated with a carrier aggregation configuration or a dualconnectivity configuration (e.g., when multiple serving cells have asuboptimal or non-ideal backhaul link). An eCC may also be configuredfor use in unlicensed spectrum or shared spectrum (where more than oneoperator is allowed to use the spectrum). An eCC characterized by widebandwidth may include one or more segments that may be utilized by UEs115 that are not capable of monitoring the whole bandwidth or prefer touse a limited bandwidth (e.g., to conserve power).

In some cases, an eCC may utilize a different symbol duration than otherCCs, which may include use of a reduced symbol duration as compared withsymbol durations of the other CCs. A shorter symbol duration may beassociated with increased subcarrier spacing. A TTI in an eCC mayconsist of one or multiple symbols. In some cases, the TTI duration(that is, the number of symbols in a TTI) may be variable. In somecases, an eCC may utilize a different symbol duration than other CCs,which may include use of a reduced symbol duration as compared withsymbol durations of the other CCs. A shorter symbol duration isassociated with increased subcarrier spacing. A device, such as a UE 115or base station 105, utilizing eCCs may transmit wideband signals (e.g.,20, 40, 60, 80 MHz, etc.) at reduced symbol durations (e.g., 16.67microseconds (μs)). A TTI in eCC may consist of one or multiple symbols.In some cases, the TTI duration (that is, the number of symbols in aTTI) may be variable.

In wireless communications system 100, a UE 115 may be expected tomonitor radio link quality to determine whether communications withanother wireless device (e.g., a base station 105, another UE 115, etc.)are synchronized (e.g., in-sync) or unsynchronized (e.g., out-of-sync),where the latter case may lead to radio link failure and a droppedcommunications session if link quality does not improve. In determiningwhether the UE 115 is in-sync or out-of-sync with another wirelessdevice, the UE 115 may use a number of RLM counters and timers. Forinstance, an N310 counter may define the number of intervals over whichthe UE 115 is unable to decode a control channel. The N310 counter maybe used to begin a T310 timer during which the UE 115 determines whetherit can get back in-sync with the wireless device. Additionally, an N311counter may define the number of intervals that the UE 115 must decode acontrol channel before it is determined to be back in-sync with thewireless device. As an illustrative example, upon receiving N310consecutive out-of-sync indications to higher layers, a UE 115 may startthe T310 timer, and upon expiration of the T310 timer, a radio linkfailure may be declared. However, if N311 consecutive in-syncindications to higher layers are received while the T310 timer isrunning, the UE 115 may stop the T310 timer. In some cases, eachout-of-sync and in-sync indication may be a certain duration (e.g., 10ms) apart. That is, the UE 115 may determine every 10 ms whether it isin-sync or out-of-sync when communicating with other wireless devices.

In some cases, a UE 115 may monitor a wireless link 125 continuously foran indication that the UE 115 may receive data. In other cases (e.g., toconserve power and extend battery life) a UE 115 may be configured witha DRX cycle. A DRX cycle consists of an “On Duration” when the UE 115may monitor for control information (e.g., on PDCCH) and a “DRX period”when the UE 115 may power down radio components. In some cases, a UE 115may be configured with a short DRX cycle and a long DRX cycle. In somecases, a UE 115 may enter a long DRX cycle if the UE 115 is inactive forone or more short DRX cycles. The transition between the short DRXcycle, the long DRX cycle and continuous reception may be controlled byan internal timer or by messaging from a base station 105. A UE 115 mayreceive scheduling messages on PDCCH during the On Duration.Additionally, the UE 115 may be configured with DRX periodicity thatenables monitoring for RSs at discrete times, or within transmissionwindows.

Wireless communications system 100 may support the use of a DRXperiodicity to enable monitoring of an RS (e.g., associated with adownlink control channel) used for RLM procedures. For example, a basestation 105 may configure a DRX periodicity for an RS, where theconfigured DRX periodicity may include a periodicity of discretetransmissions of the RS or a periodicity of a transmission window inwhich the RS is located (e.g., within at least one TTI of respectivetransmission windows). Accordingly, a UE 115 may identify the DRXperiodicity and monitor radio link quality using the RS based on the DRXperiodicity. In some examples, the RS may be transmitted independent ofcontrol channel transmissions, and the base station 105 may configureone or more control resource sets for the RS. Additionally, the UE 115may opportunistically monitor radio link quality independent of theconfigured DRX periodicity associated with the RS (e.g., the receivingdevice may monitor radio link quality outside of the configured discretetransmissions or transmission windows).

FIG. 2 illustrates an example of a wireless communications system 200that supports RLM without always-on RSs in accordance with variousaspects of the present disclosure. Wireless communications system 200includes a UE 115-a and base station 105-a, which may be examples of thecorresponding devices as described with reference to FIG. 1. Wirelesscommunications system 200 may be an example of a system that does notuse an always-on RS (such as a CRS), but utilizes a configured RS fordownlink control channels that enables a UE 115 to perform RLMprocedures.

For example, RLM within wireless communications system 200 may utilize aconfigured (or a guaranteed) periodicity of an RS 210 for downlinkcontrol channels. In such cases, UE 115-a may monitor downlink radiolink quality at certain intervals based on a DRX periodicity associatedwith an RS 210 for a downlink control channel. The DRX periodicity mayinclude a discrete periodicity for transmissions of the RS 210. In somecases, UE 115-a may opportunistically monitor downlink radio linkquality outside or independent of the configured occasions (e.g., thediscrete periodicity) when UE 115-a detects a presence of the RS 210. Insome examples, RS 210 may include a CRS, a channel state information RS(CSI-RS), a synchronization signal burst (SSB), a demodulation referencesignal (DMRS), or other types of RSs.

Additionally or alternatively, the RS 210 may be transmitted within acertain window. That is, the DRX periodicity may include a periodicityof a transmission window for the RS 210, and UE 115-a may monitor fortransmissions of the RS 210 during the transmission window for RLMpurposes. Transmitting the RS 210 within at least one TTI (e.g., a slot)of the transmission window may allow jittering of transmission occasionsof the RS 210, and may enable scheduling flexibility for base station105-a. Accordingly, UE 115-a may monitor downlink radio link quality ofthe RS(s) 210 within the configured transmission window. In such cases,UE 115-a may determine signal-to-noise ratios (SNRs) of RSs withinrespective transmission windows, and select an RS in a particulartransmission window for use in RLM procedures based on the SNRs. In somecases, UE 115-a may select the RS with the highest SNR (e.g., an RShaving a highest quality) relative to SNRs of other RSs. Additionally oralternatively, UE 115-a may opportunistically take (e.g., measure) anySNRs of RSs from other slots within a window when UE 115-a detects thepresence of the RS 210. In some examples, UE 115-a may monitor downlinkradio link quality outside of the configured transmission window when UE115-a detects the presence of the RS 210.

Base station 105-b may indicate the DRX periodicity to UE 115-a usingRRC signaling, or may transmit the DRX periodicity using a systeminformation broadcast. In some cases, such as when the DRX periodicitycomprises a transmission window, the indication may include a size,duration, or length of the transmission window. As a result, UE 115-amay determine the periodicity of the window and the length of the windowto assist UE 115-a in monitoring for the RSs 210.

The use of the RS 210 within a window may enable base station 105-a totransmit the RS 210 independent of the presence of a control channelwithin the window, at least for a single slot according to theconfigured window periodicities on configured resources. In some cases,if UE 115-a does not detect any presence of the RS 210 within atransmission window (e.g., because of a low RS SNR), UE 115-a may selectthe RS with the highest SNR within a transmission window to use for RLMprocedures.

In some cases, the RS 210 may be associated with certain control channelresource sets. For example, the RS may be associated with common controlchannels, UE-specific control channels, group specific control channels,or a combination thereof. That is, base station 105-a may configure morethan one control resource sets for the purpose of RLM for UE 115-a.Accordingly, base station 105-a may configure which control resourcesets provide the RS 210. In such cases, base station 105-a may transmitthe RS 210 independent of a control channel (e.g., a control channel maynot be present at the DRX periodicity when the RS 210 is transmitted),which may be in accordance with configured periodicities on configuredresources. The configured DRX periodicity may enable the avoidance ofambiguity between RSs with a low SNR and muted RSs at UE 115-a.

In some cases, base station 105-a may configure more than one controlchannel resource set for the purpose of RLM. UE 115-a may accordinglyuse one control resource set (e.g., a control resource set that includesa primary common PDCCH) as a default set for an SNR measurement.Additionally or alternatively, UE 115-a may optionally use other controlresource sets for SNR measurements, where measurement accuracy may notbe any worse than using the default resource set. In some cases, UE115-a may use all of the configured control resource sets formeasurements, using a combined SNR or a maximum SNR among all of thesets for RLM.

Upon decoding a downlink control channel, UE 115-a may use differenttechniques to manage RLM counters and timers. For example, uponsuccessfully decoding the downlink control channel, UE 115-a may reset afirst RLM counter (e.g., an N310 counter). Additionally oralternatively, UE 115-a may boost a second RLM counter (e.g., an N311counter), where boosting the counter may include increasing an amount bywhich the counter increments (e.g., by a certain boosting factor). Forexample, where the N311 counter may initially increment by one, the N311counter may increment by five after being boosted. In some cases,different control channels (e.g., common control and UE-specific controlchannels) may have different boosting factors associated with them,where, for example, decoding a UE-specific control channel may beassociated with a larger boosting factor than decoding a common controlchannel. Additionally or alternatively, aggregation level information ofa decoded downlink control channel may also be reflected in the boostingfactor (e.g., a smaller aggregation level may have a larger boostingfactor).

In some cases, wireless communications system 200 may use an indicationthat signals single beam or multiple beam communications within thesystem. For example, base station 105-a may transmit a multi-beamindication to UE 115-a that signals that communications within wirelesscommunications system 200 utilize multiple directional beams (notshown). Alternatively, a single beam indication may be transmitted to UE115-a that signals a deployment that utilizes single beam transmissions.In some cases, the indication may be sent using different signalingschemes, such as via synchronization signals (e.g., included in an SSB),a master information block (MIB), a system information block (SIB), anRRC configuration, or the like. Accordingly, the use of the RS 210 forRLM procedures described herein may be implemented in single beam andmulti-beam deployments.

FIG. 3 illustrates an example of a DRX configuration 300 that supportsRLM without always-on RSs in accordance with various aspects of thepresent disclosure. DRX configuration 300 illustrates an example of aDRX periodicity for discrete transmissions of an RS for a downlinkcontrol channel for RLM procedures.

DRX configuration 300 may include a DRX periodicity 305 including a DRXOn duration and a DRX Off duration. The DRX periodicity 305 may beconfigured by a transmitting device (e.g., a base station 105) such thata receiving device (e.g., a UE 115) may wake up during a DRX On durationto monitor for transmissions of an RS 310 for a downlink control channel(e.g., including at least a first RS 310-a for a downlink controlchannel, a second RS 310-b for a downlink control channel, and so forth)for RLM procedures. DRX configuration 300 may support a periodicity ofdiscrete transmissions of RS 310, which a UE 115 may use for monitoringradio link quality (e.g., in a system that does not use always-ontransmissions of a CRS). Accordingly, each DRX On duration within theDRX periodicity may provide the UE 115 a configured (or guaranteed) timeduring which the RS 310 is transmitted, and the UE 115 may performmeasurements of the quality of the RS 310. For example, the UE 115 maymeasure an SNR of the RS 310, a signal-to-interference plus noise ratio(SINR) of the RS310, or a bit error rate of RS 310 to determine thequality of RS310. In some examples, a UE may perform the RLM proceduresusing a hypothetical downlink control channel (e.g., based on a qualityor SNR of an RS that is associated with a hypothetical PDCCH).

In some cases, each transmission of RSs 310 may be independent of apresence of a control channel. For instance, the transmission of acontrol channel may not coincide with, or occur at a different timethan, the transmission of RSs 310. Additionally, a base station 105 mayconfigure control channel resource sets (e.g., resource blocks), whichmay be associated with common control channels and/or UE-specificcontrol channels. The transmission of the discrete RSs 310 according tothe DRX periodicity 305 may circumvent ambiguity in different RSs 310received, such as an RS 310 having a low SNR and muted RSs 310.

A UE 115 may monitor downlink radio link quality outside of theconfigured occasions when the UE 115 detects the presence of the RS 310.As an example, the UE 115 may opportunistically monitor radio linkquality at instances either before or after the transmission of an RS310 for a downlink control channel.

FIG. 4 illustrates an example of a DRX configuration 400 that supportsRLM without always-on RSs in accordance with various aspects of thepresent disclosure. DRX configuration 400 illustrates an example of aDRX periodicity for transmission windows, where respective transmissionwindows include a transmission of an RS for a downlink control channeland used for RLM procedures.

DRX configuration 400 may include a DRX periodicity 405 including a DRXOn duration and a DRX Off duration. The DRX periodicity 405 may beconfigured by a transmitting device (e.g., a base station 105) such thata receiving device (e.g., a UE 115) may wake up during a DRX On durationto monitor for transmissions of an RS 410 for a downlink control channel(e.g., including at least a first RS 410-a, a second RS 410-b, and soforth). DRX configuration 400 may support a configuration of aperiodicity of transmission windows 415, where each transmission window415 may include a respective transmission of RS 410 that a UE 115 mayuse for monitoring radio link quality (e.g., in a system that does notuse always-on transmissions of a CRS). For example, a first transmissionwindow 415-a may include the first RS 410-a, which may be included in atleast one TTI (e.g., slot) of the first transmission window 415-a.Likewise, a second transmission window 415-b may include the second RS410-b during at least one TTI, and so forth.

Accordingly, each DRX On duration within DRX periodicity 405 may providethe UE 115 a configured (or guaranteed) window during which an RS 410for a downlink control channel is transmitted. In some cases, the UE 115may take a highest SNR within a transmission window 415 for RLMprocedures. Additionally or alternatively, the UE 115 may take SNRs fromother TTIs within the transmission window 415 when the presence of RS410 is detected. The use of the transmission windows 415 may enablejittering of the transmission of the RS 410, which may providescheduling flexibility for the transmitter.

Additionally or alternatively, a UE 115 may monitor downlink radio linkquality outside of the configured transmission windows 415 when the UE115 detects the presence of the RS 410. As an example, the UE 115 mayopportunistically monitor radio link quality at instances either beforeor after the transmission windows 415. In some cases, the RS 410 withina transmission window 415 may be transmitted independently of a presenceof a control channel.

FIG. 5 illustrates an example of a process flow 500 in a system thatsupports RLM without always-on RSs in accordance with various aspects ofthe present disclosure. Process flow 500 includes a UE 115-b and basestation 105-b, which may be examples of the corresponding devices asdescribed with reference to FIGS. 1 and 2. Process flow 500 illustratesan example of the use of an RS for downlink control channels, where theRS is used for RLM procedures in a system that does not includetransmissions of an always-on RS (such as a CRS).

At 505, base station 105-b may identify an RS that may be associatedwith RLM procedures. The RS may be associated with a downlink controlchannel (e.g., PDCCH or ePDCCH). At 505, base station 105-b mayconfigure a DRX periodicity for the RS. In some cases, configuring theDRX periodicity for the RS may include configuring a periodicity ofdiscrete transmissions of the RS. Additionally or alternatively,configuring the DRX periodicity for the RS may include configuring aperiodicity of transmission windows for the RS, wherein the RS istransmitted within respective transmission windows. In such cases, atleast one TTI within the respective transmission windows may include theRS.

In some cases, the DRX periodicity for the RS may be independent ofcontrol channel transmissions from base station 105-b. At 510, basestation 105-b may also configure one or more control resource setsassociated with transmission of the RS associated with the RLMprocedures. In such cases, the control resource sets may includeresources associated with a common control channel or resourcesassociated with a UE-specific control channel.

At 515, base station 105-b may transmit, and UE 115-b may receive, anindication of the DRX configuration. That is, base station 105-b maysignal to UE 115-b the configured DRX periodicity for the RS. In somecases, the indication may be transmitted using RRC signaling, systeminformation broadcast signaling, or a combination thereof. In someexamples, base station 105-b may transmit an indication of a length ofthe respective transmission windows.

At 520, UE 115-b may identify the DRX periodicity for the RS associatedwith the RLM procedures. For example, identifying the DRX periodicityfor the RS may include determining a periodicity of discretetransmissions of the RS. Additionally or alternatively, identifying theDRX periodicity for the RS may include determining a periodicity oftransmission windows for the RS, wherein the RS is received withinrespective transmission windows. In such cases, UE 115-b may use ahighest SNR within respective transmission windows for the RLMprocedures, or may use an SNR associated with one or more TTIs (e.g., aslot) within respective transmission windows for the RLM procedures.

At 520, UE 115-b may identify one or more control resource setsassociated with receiving the RS associated with the RLM procedures. Insome cases, UE 115-b may identify a first control resource set, identifya second control resource set associated with receiving the RS, and useat least the first control resource set, the second control resourceset, or a combination thereof for the RLM procedures. For instance, UE115-b may select the first control resource set as a default set (whichmay correspond to a control resource set associated with a primarycommon PDCCH). UE 115-b may optionally use the second control resourceset (or other control resource sets) for radio link quality measurementsin cases where the accuracy of the measurements on the second controlresource set are not worse than measurements on the first controlresource set.

At 525, UE 115-b may monitor radio link quality based at least in parton the identified DRX periodicity. In some examples, UE 115-b may detecta presence of the RS and monitor radio link quality independent of theperiodicity of the discrete transmissions. In other cases, UE 115-b maymonitor the radio link quality independent of the periodicity of thetransmission windows based on the detected presence of the RS.

At 530, base station 105-b may transmit, and UE 115-b may receive, theRS according to the DRX periodicity. At 535, base station may transmit adownlink control channel to UE 115-b. Upon decoding the downlink controlchannel, UE 115-b may reset and/or boost an RLM counter based onsuccessfully decoding the control channel. For instance, at 540, UE115-b may decode the control channel and reset an N310 counter.Additionally or alternatively, UE 115-b may decode the control channeland boost an N311 counter at 540. In some cases, boosting the N311counter (e.g., according to a boosting factor) may be based on a type ofcontrol channel resources associated with the control channel, or may bebased on an aggregation level of the control channel.

FIG. 6 shows a block diagram 600 of a wireless device 605 that supportsRLM without always-on RSs in accordance with aspects of the presentdisclosure. Wireless device 605 may be an example of aspects of areceiving device, such as a UE 115, as described with reference toFIG. 1. Wireless device 605 may include receiver 610, UE RLM manager615, and transmitter 620. Wireless device 605 may also include aprocessor. Each of these components may be in communication with oneanother (e.g., via one or more buses).

Receiver 610 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to RLM withoutalways-on RSs, etc.). Information may be passed on to other componentsof the device. The receiver 610 may be an example of aspects of thetransceiver 935 described with reference to FIG. 9. The receiver 610 mayutilize a single antenna or a set of antennas.

UE RLM manager 615 may be an example of aspects of the UE RLM manager915 described with reference to FIG. 9. UE RLM manager 615 and/or atleast some of its various sub-components may be implemented in hardware,software executed by a processor, firmware, or any combination thereof.If implemented in software executed by a processor, the functions of theUE RLM manager 615 and/or at least some of its various sub-componentsmay be executed by a general-purpose processor, a digital signalprocessor (DSP), an application-specific integrated circuit (ASIC), anfield-programmable gate array (FPGA) or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described in thepresent disclosure.

The UE RLM manager 615 and/or at least some of its varioussub-components may be physically located at various positions, includingbeing distributed such that portions of functions are implemented atdifferent physical locations by one or more physical devices. In someexamples, UE RLM manager 615 and/or at least some of its varioussub-components may be a separate and distinct component in accordancewith various aspects of the present disclosure. In other examples, UERLM manager 615 and/or at least some of its various sub-components maybe combined with one or more other hardware components, including butnot limited to an input/output (I/O) component, a transceiver, a networkserver, another computing device, one or more other components describedin the present disclosure, or a combination thereof in accordance withvarious aspects of the present disclosure.

UE RLM manager 615 may identify a DRX periodicity for an RS for adownlink control channel, where the RS may be associated with RLMprocedures, monitor a radio link quality based on the identified DRXperiodicity, and receive the RS according to the DRX periodicity.

Transmitter 620 may transmit signals generated by other components ofthe device. In some examples, the transmitter 620 may be collocated witha receiver 610 in a transceiver module. For example, the transmitter 620may be an example of aspects of the transceiver 935 described withreference to FIG. 9. The transmitter 620 may utilize a single antenna ora set of antennas.

FIG. 7 shows a block diagram 700 of a wireless device 705 that supportsRLM without always-on RSs in accordance with aspects of the presentdisclosure. Wireless device 705 may be an example of aspects of awireless device 605 or a UE 115 as described with reference to FIGS. 1and 6. Wireless device 705 may include receiver 710, UE RLM manager 715,and transmitter 720. Wireless device 705 may also include a processor.Each of these components may be in communication with one another (e.g.,via one or more buses).

Receiver 710 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to RLM withoutalways-on RSs, etc.). Information may be passed on to other componentsof the device. The receiver 710 may be an example of aspects of thetransceiver 935 described with reference to FIG. 9. The receiver 710 mayutilize a single antenna or a set of antennas. UE RLM manager 715 may bean example of aspects of the UE RLM manager 915 described with referenceto FIG. 9. UE RLM manager 715 may also include DRX periodicity manager725, radio link monitoring component 730, and RS manager 735.

DRX periodicity manager 725 may identify a DRX periodicity for an RS fora downlink control channel, where the RS may be associated with RLMprocedures. In some cases, identifying the DRX periodicity for the RSincludes determining a periodicity of discrete transmissions of the RS.Additionally or alternatively, identifying the DRX periodicity for theRS includes determining a periodicity of transmission windows for theRS, where the RS is received within respective transmission windows. Insome cases, at least one TTI within the respective transmission windowsincludes the RS. In some cases, the DRX periodicity for the RS isindependent of reception of control channels.

In some cases, DRX periodicity manager 725 may receive an indication ofa length of the respective transmission windows, where the indication isreceived via RRC signaling, system information broadcast signaling, or acombination thereof. Additionally, DRX periodicity manager 725 mayreceive an indication of the DRX periodicity, where the indication isalso received via RRC signaling, system information broadcast signaling,or a combination thereof.

Radio link monitoring component 730 may monitor a radio link qualitybased on the identified DRX periodicity. In some cases, radio linkmonitoring component 730 may monitor the radio link quality independentof the periodicity of the discrete transmissions based on the detectedpresence of the RS. Additionally, or alternatively, radio linkmonitoring component 730 may monitor the radio link quality independentof the periodicity of the transmission windows based on the detectedpresence of the RS. In such cases, radio link monitoring component 730may use a highest SNR within respective transmission windows for the RLMprocedures or use a SNR associated with one or more TTIs withinrespective transmission windows for the RLM procedures, or a combinationthereof.

In some examples, radio link monitoring component 730 may use at least afirst control resource set, a second control resource set, or acombination thereof for the RLM procedures. RS manager 735 may receivethe RS according to the DRX periodicity and detect a presence of the RS.

Transmitter 720 may transmit signals generated by other components ofthe device. In some examples, the transmitter 720 may be collocated witha receiver 710 in a transceiver module. For example, the transmitter 720may be an example of aspects of the transceiver 935 described withreference to FIG. 9. The transmitter 720 may utilize a single antenna ora set of antennas.

FIG. 8 shows a block diagram 800 of a UE RLM manager 815 that supportsRLM without always-on RSs in accordance with aspects of the presentdisclosure. The UE RLM manager 815 may be an example of aspects of a UERLM manager 615, a UE RLM manager 715, or a UE RLM manager 915 describedwith reference to FIGS. 6, 7, and 9. The UE RLM manager 815 may includeDRX periodicity manager 820, radio link monitoring component 825, RSmanager 830, control resource set component 835, decoder 840, and RLMcounter manager 845. Each of these modules may communicate, directly orindirectly, with one another (e.g., via one or more buses).

DRX periodicity manager 820 may identify a DRX periodicity for an RS fora downlink control channel, where the RS may be associated with RLMprocedures. In some cases, identifying the DRX periodicity for the RSincludes determining a periodicity of discrete transmissions of the RS.Additionally or alternatively, identifying the DRX periodicity for theRS includes determining a periodicity of transmission windows for theRS, where the RS is received within respective transmission windows. Insome cases, at least one TTI within the respective transmission windowsincludes the RS. For instance, each of the respective transmissionwindows may be comprised of one or more TTIs (e.g., slots), and the RSmay be transmitted by a base station 105 within at least one of theslots. In some cases, the DRX periodicity for the RS is independent ofreception of control channels.

In some cases, DRX periodicity manager 820 may receive an indication ofa length of the respective transmission windows, where the indication isreceived via RRC signaling, system information broadcast signaling, or acombination thereof. Additionally, DRX periodicity manager 820 mayreceive an indication of the DRX periodicity, where the indication isalso received via RRC signaling, system information broadcast signaling,or a combination thereof.

Radio link monitoring component 825 may monitor a radio link qualitybased on the identified DRX periodicity and monitor the radio linkquality independent of the periodicity of the discrete transmissionsbased on the detected presence of the RS. In some examples, radio linkmonitoring component 825 may monitor the radio link quality independentof the periodicity of the transmission windows based on the detectedpresence of the RS. In some cases, radio link monitoring component 825may use a highest SNR within respective transmission windows for the RLMprocedures. Additionally or alternatively, radio link monitoringcomponent 825 may use an SNR associated with one or more TTIs withinrespective transmission windows for the RLM procedures. In someexamples, radio link monitoring component 825 may use at least the firstcontrol resource set, the second control resource set, or a combinationthereof for the RLM procedures.

RS manager 830 may receive the RS according to the DRX periodicity anddetect a presence of the RS. Control resource set component 835 mayidentify one or more control resource sets associated with receiving theRS associated with the RLM procedures. In some cases, control resourceset component 835 may identify a first control resource set associatedwith receiving the RS and identify a second control resource setassociated with receiving the RS. In some cases, the one or more controlresource sets include at least resources associated with a commoncontrol channel or resources associated with a UE-specific controlchannel.

Decoder 840 may decode a downlink control channel. RLM counter manager845 may reset an RLM counter based on the decoded downlink controlchannel. Additionally or alternatively, RLM counter manager 845 mayboost an RLM counter based on the decoded downlink control channel. Insome cases, boosting the RLM counter may include identifying anaggregation level associated with the downlink control channel andboosting the RLM counter based on the identified aggregation level.Additionally or alternatively, boosting the RLM counter may includeidentifying a type of control channel resources associated with thedownlink control channel (e.g., common control, group-specific, orUE-specific) and boosting the RLM counter based on the identified typeof control channel resources.

FIG. 9 shows a diagram of a system 900 including a device 905 thatsupports RLM without always-on RSs in accordance with aspects of thepresent disclosure. Device 905 may be an example of or include thecomponents of wireless device 605, wireless device 705, or a UE 115 asdescribed above, e.g., with reference to FIGS. 1, 6 and 7. Device 905may include components for bi-directional voice and data communicationsincluding components for transmitting and receiving communications,including UE RLM manager 915, processor 920, memory 925, software 930,transceiver 935, antenna 940, and I/O controller 945. These componentsmay be in electronic communication via one or more busses (e.g., bus910). Device 905 may communicate wirelessly with one or more basestations 105.

Processor 920 may include an intelligent hardware device, (e.g., ageneral-purpose processor, a DSP, a central processing unit (CPU), amicrocontroller, an ASIC, an FPGA, a programmable logic device, adiscrete gate or transistor logic component, a discrete hardwarecomponent, or any combination thereof). In some cases, processor 920 maybe configured to operate a memory array using a memory controller. Inother cases, a memory controller may be integrated into processor 920.Processor 920 may be configured to execute computer-readableinstructions stored in a memory to perform various functions (e.g.,functions or tasks supporting RLM without always-on RSs). For example,processor 920 may be configured to execute instructions to identify aDRX periodicity for an RS and monitor a radio link quality using theidentified DRX periodicity. Processor 920 may also be configured toexecute instructions to detect or select an RS, decode a downlinkcontrol channel, reset or boost an RLM counter, and/or measure thequality of an RS, among other functions.

Memory 925 may include random-access memory (RAM) and read-only memory(ROM). The memory 925 may store computer-readable, computer-executablesoftware 930 including instructions that, when executed, cause theprocessor to perform various functions described herein. In some cases,the memory 925 may contain, among other things, a basic input/outputsystem (BIOS) which may control basic hardware and/or software operationsuch as the interaction with peripheral components or devices.

Software 930 may include code to implement aspects of the presentdisclosure, including code to support RLM without always-on RSs.Software 930 may be stored in a non-transitory computer-readable mediumsuch as system memory or other memory. In some cases, the software 930may not be directly executable by the processor but may cause a computer(e.g., when compiled and executed) to perform functions describedherein.

Transceiver 935 may communicate bi-directionally, via one or moreantennas, wired, or wireless links as described above. For example, thetransceiver 935 may represent a wireless transceiver and may communicatebi-directionally with another wireless transceiver. The transceiver 935may also include a modem to modulate the packets and provide themodulated packets to the antennas for transmission, and to demodulatepackets received from the antennas. In some cases, the wireless devicemay include a single antenna 940. However, in some cases the device mayhave more than one antenna 940, which may be capable of concurrentlytransmitting or receiving multiple wireless transmissions. Transceiver935 may, for example, receive an RS, receive an indication of a lengthof a transmission window, and/or receive an indication of a DRXperiodicity.

I/O controller 945 may manage input and output signals for device 905.I/O controller 945 may also manage peripherals not integrated intodevice 905. In some cases, I/O controller 945 may represent a physicalconnection or port to an external peripheral. In some cases, I/Ocontroller 945 may utilize an operating system such as iOS®, ANDROID®,MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, or another known operatingsystem. In other cases, I/O controller 945 may represent or interactwith a modem, a keyboard, a mouse, a touchscreen, or a similar device.In some cases, I/O controller 945 may be implemented as part of aprocessor. In some cases, a user may interact with device 905 via I/Ocontroller 945 or via hardware components controlled by I/O controller945.

FIG. 10 shows a block diagram 1000 of a wireless device 1005 thatsupports RLM without always-on RSs in accordance with aspects of thepresent disclosure. Wireless device 1005 may be an example of aspects ofa transmitting device, such as a base station 105, as described withreference to FIG. 1. Wireless device 1005 may include receiver 1010,base station RLM manager 1015, and transmitter 1020. Wireless device1005 may also include a processor. Each of these components may be incommunication with one another (e.g., via one or more buses).

Receiver 1010 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to RLM withoutalways-on RSs, etc.). Information may be passed on to other componentsof the device. The receiver 1010 may be an example of aspects of thetransceiver 1335 described with reference to FIG. 13. The receiver 1010may utilize a single antenna or a set of antennas.

Base station RLM manager 1015 may be an example of aspects of the basestation RLM manager 1315 described with reference to FIG. 13. Basestation RLM manager 1015 and/or at least some of its varioussub-components may be implemented in hardware, software executed by aprocessor, firmware, or any combination thereof. If implemented insoftware executed by a processor, the functions of the base station RLMmanager 1015 and/or at least some of its various sub-components may beexecuted by a general-purpose processor, a DSP, an ASIC, an FPGA orother programmable logic device, discrete gate or transistor logic,discrete hardware components, or any combination thereof designed toperform the functions described in the present disclosure.

The base station RLM manager 1015 and/or at least some of its varioussub-components may be physically located at various positions, includingbeing distributed such that portions of functions are implemented atdifferent physical locations by one or more physical devices. In someexamples, base station RLM manager 1015 and/or at least some of itsvarious sub-components may be a separate and distinct component inaccordance with various aspects of the present disclosure. In otherexamples, base station RLM manager 1015 and/or at least some of itsvarious sub-components may be combined with one or more other hardwarecomponents, including but not limited to an I/O component, atransceiver, a network server, another computing device, one or moreother components described in the present disclosure, or a combinationthereof in accordance with various aspects of the present disclosure.

Base station RLM manager 1015 may identify an RS for a downlink controlchannel, where the RS may be associated with RLM procedures andconfigure a DRX periodicity for the RS. Transmitter 1020 may transmitsignals generated by other components of the device. In some examples,the transmitter 1020 may be collocated with a receiver 1010 in atransceiver module. For example, the transmitter 1020 may be an exampleof aspects of the transceiver 1335 described with reference to FIG. 13.The transmitter 1020 may utilize a single antenna or a set of antennas.In some examples, transmitter 1020 may transmit the RS according to theconfigured DRX periodicity.

FIG. 11 shows a block diagram 1100 of a wireless device 1105 thatsupports RLM without always-on RSs in accordance with aspects of thepresent disclosure. Wireless device 1105 may be an example of aspects ofa wireless device 1005 or a base station 105 as described with referenceto FIGS. 1 and 10. Wireless device 1105 may include receiver 1110, basestation RLM manager 1115, and transmitter 1120. Wireless device 1105 mayalso include a processor. Each of these components may be incommunication with one another (e.g., via one or more buses).

Receiver 1110 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to RLM withoutalways-on RSs, etc.). Information may be passed on to other componentsof the device. The receiver 1110 may be an example of aspects of thetransceiver 1335 described with reference to FIG. 13. The receiver 1110may utilize a single antenna or a set of antennas.

Base station RLM manager 1115 may be an example of aspects of the basestation RLM manager 1315 described with reference to FIG. 13. Basestation RLM manager 1115 may also include downlink RS component 1125 andDRX configuration manager 1130. Downlink RS component 1125 may identifyan RS that may be associated with RLM procedures. The RS may beassociated with a downlink control channel.

DRX configuration manager 1130 may configure a DRX periodicity for theRS. In some cases, configuring the DRX periodicity for the RS mayinclude configuring a periodicity of discrete transmissions of the RS.Additionally or alternatively, configuring the DRX periodicity for theRS may include configuring a periodicity of transmission windows for theRS, where the RS is transmitted within respective transmission windows.In some cases, each of the respective transmission windows comprises oneor more TTIs, and the RS may be included within at least one TTI of theone or more TTIs. In some cases, the DRX periodicity for the RS isindependent of control channel transmissions. In some cases, DRXconfiguration manager 1130 may transmit an indication of a length of therespective transmission windows, where the indication is transmitted viaRRC signaling, system information broadcast signaling, or a combinationthereof.

Transmitter 1120 may transmit signals generated by other components ofthe device. In some examples, the transmitter 1120 may be collocatedwith a receiver 1110 in a transceiver module. For example, thetransmitter 1120 may be an example of aspects of the transceiver 1335described with reference to FIG. 13. The transmitter 1120 may utilize asingle antenna or a set of antennas. In some examples, transmitter 1120may transmit the RS according to the configured DRX periodicity.

FIG. 12 shows a block diagram 1200 of a base station RLM manager 1215that supports RLM without always-on RSs in accordance with aspects ofthe present disclosure. The base station RLM manager 1215 may be anexample of aspects of a base station RLM manager 1315 described withreference to FIGS. 10, 11, and 13. The base station RLM manager 1215 mayinclude downlink RS component 1220, DRX configuration manager 1225,control resource set manager 1230, and DRX indication manager 1235. Eachof these modules may communicate, directly or indirectly, with oneanother (e.g., via one or more buses).

Downlink RS component 1220 may identify an RS that may be associatedwith RLM procedures. The RS may be associated with a downlink controlchannel. DRX configuration manager 1225 may configure a DRX periodicityfor the RS. In some cases, configuring the DRX periodicity for the RSmay include configuring a periodicity of discrete transmissions of theRS. Additionally or alternatively, configuring the DRX periodicity forthe RS may include configuring a periodicity of transmission windows forthe RS, where the RS is transmitted within respective transmissionwindows. In some cases, at least one TTI within the respectivetransmission windows includes the RS. In some cases, the DRX periodicityfor the RS is independent of control channel transmissions. In somecases, DRX configuration manager 1225 may transmit an indication of alength of the respective transmission windows, where the indication istransmitted via RRC signaling, system information broadcast signaling,or a combination thereof.

Control resource set manager 1230 may configure one or more controlresource sets for transmission of the RS associated with the RLMprocedures. In some cases, the one or more control resource sets includeat least resources associated with a common control channel or resourcesassociated with a UE-specific control channel. DRX indication manager1235 may transmit an indication of the configured DRX periodicity, wherethe indication is transmitted using RRC signaling, system informationbroadcast signaling, or a combination thereof.

FIG. 13 shows a diagram of a system 1300 including a device 1305 thatsupports RLM without always-on RSs in accordance with aspects of thepresent disclosure. Device 1305 may be an example of or include thecomponents of base station 105 as described above, e.g., with referenceto FIG. 1. Device 1305 may include components for bi-directional voiceand data communications including components for transmitting andreceiving communications, including base station RLM manager 1315,processor 1320, memory 1325, software 1330, transceiver 1335, antenna1340, network communications manager 1345, and inter-stationcommunications manager 1350. These components may be in electroniccommunication via one or more busses (e.g., bus 1310). Device 1305 maycommunicate wirelessly with one or more UEs 115.

Processor 1320 may include an intelligent hardware device, (e.g., ageneral-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, anFPGA, a programmable logic device, a discrete gate or transistor logiccomponent, a discrete hardware component, or any combination thereof).In some cases, processor 1320 may be configured to operate a memoryarray using a memory controller. In other cases, a memory controller maybe integrated into processor 1320. Processor 1320 may be configured toexecute computer-readable instructions stored in a memory to performvarious functions (e.g., functions or tasks supporting RLM withoutalways-on RSs). For example, processor 1320 may be configured to executecomputer-readable instructions to identify an RS, configure a DRXperiodicity for the RS, configure a periodicity of discretetransmissions and/or of transmission windows for the RS, and/orconfigure control resource sets, among other functions.

Memory 1325 may include RAM and ROM. The memory 1325 may storecomputer-readable, computer-executable software 1330 includinginstructions that, when executed, cause the processor to perform variousfunctions described herein. In some cases, the memory 1325 may contain,among other things, a BIOS which may control basic hardware and/orsoftware operation such as the interaction with peripheral components ordevices.

Software 1330 may include code to implement aspects of the presentdisclosure, including code to support RLM without always-on RSs.Software 1330 may be stored in a non-transitory computer-readable mediumsuch as system memory or other memory. In some cases, the software 1330may not be directly executable by the processor but may cause a computer(e.g., when compiled and executed) to perform functions describedherein.

Transceiver 1335 may communicate bi-directionally, via one or moreantennas, wired, or wireless links as described above. For example, thetransceiver 1335 may represent a wireless transceiver and maycommunicate bi-directionally with another wireless transceiver. Thetransceiver 1335 may also include a modem to modulate the packets andprovide the modulated packets to the antennas for transmission, and todemodulate packets received from the antennas. In some cases, thewireless device may include a single antenna 1340. However, in somecases the device may have more than one antenna 1340, which may becapable of concurrently transmitting or receiving multiple wirelesstransmissions. Transceiver 1335 may, for example, transmit an RS,transmit an indication of a length of a transmission window, and/ortransmit an indication of the configured DRX periodicity.

Network communications manager 1345 may manage communications with thecore network (e.g., via one or more wired backhaul links). For example,the network communications manager 1345 may manage the transfer of datacommunications for client devices, such as one or more UEs 115.

Inter-station communications manager 1350 may manage communications withother base stations 105, and may include a controller or scheduler forcontrolling communications with UEs 115 in cooperation with other basestations 105. For example, the inter-station communications manager 1350may coordinate scheduling for transmissions to UEs 115 for variousinterference mitigation techniques such as beamforming or jointtransmission. In some examples, inter-station communications manager1350 may provide an X2 interface within an LTE/LTE-A wirelesscommunication network technology to provide communication between basestations 105.

FIG. 14 shows a flowchart illustrating a method 1400 for RLM withoutalways-on RSs in accordance with aspects of the present disclosure. Theoperations of method 1400 may be implemented by a receiving device, suchas a UE 115, or its components as described herein. For example, theoperations of method 1400 may be performed by a UE RLM manager asdescribed with reference to FIGS. 6 through 9. In some examples, a UE115 may execute a set of codes to control the functional elements of thedevice to perform the functions described below. Additionally oralternatively, the UE 115 may perform aspects of the functions describedbelow using special-purpose hardware.

At 1405 the UE 115 may identify a DRX periodicity for an RS associatedwith RLM procedures. The RS may be associated with a downlink controlchannel. The operations of 1405 may be performed according to themethods described with reference to FIGS. 1 through 5. In certainexamples, aspects of the operations of 1405 may be performed by a DRXperiodicity manager as described with reference to FIGS. 6 through 9.

At 1410 the UE 115 may monitor a radio link quality based at least inpart on the identified DRX periodicity. The operations of 1410 may beperformed according to the methods described with reference to FIGS. 1through 5. In certain examples, aspects of the operations of 1410 may beperformed by a radio link monitoring component as described withreference to FIGS. 6 through 9.

At 1415 the UE 115 may receive the RS according to the DRX periodicity.The operations of 1415 may be performed according to the methodsdescribed with reference to FIGS. 1 through 5. In certain examples,aspects of the operations of 1415 may be performed by an RS manager asdescribed with reference to FIGS. 6 through 9.

FIG. 15 shows a flowchart illustrating a method 1500 for RLM withoutalways-on RSs in accordance with aspects of the present disclosure. Theoperations of method 1500 may be implemented by a receiving device, suchas a UE 115, or its components as described herein. For example, theoperations of method 1500 may be performed by a UE RLM manager asdescribed with reference to FIGS. 6 through 9. In some examples, a UE115 may execute a set of codes to control the functional elements of thedevice to perform the functions described below. Additionally oralternatively, the UE 115 may perform aspects of the functions describedbelow using special-purpose hardware.

At 1505 the UE 115 may determine a periodicity of discrete transmissionsof an RS. The operations of 1505 may be performed according to themethods described with reference to FIGS. 1 through 5. In certainexamples, aspects of the operations of 1505 may be performed by a DRXperiodicity manager as described with reference to FIGS. 6 through 9.

At 1510 the UE 115 may monitor a radio link quality based at least inpart on an identified DRX periodicity. The operations of 1510 may beperformed according to the methods described with reference to FIGS. 1through 5. In certain examples, aspects of the operations of 1510 may beperformed by a radio link monitoring component as described withreference to FIGS. 6 through 9.

At 1515 the UE 115 may detect a presence of the RS. The operations of1515 may be performed according to the methods described with referenceto FIGS. 1 through 5. In certain examples, aspects of the operations of1515 may be performed by an RS manager as described with reference toFIGS. 6 through 9.

At 1520 the UE 115 may optionally (e.g., opportunistically) monitor theradio link quality independent of the periodicity of the discretetransmissions of the RS based at least in part on the detected presenceof the RS. The operations of 1520 may be performed according to themethods described with reference to FIGS. 1 through 5. In certainexamples, aspects of the operations of 1520 may be performed by a radiolink monitoring component as described with reference to FIGS. 6 through9.

FIG. 16 shows a flowchart illustrating a method 1600 for RLM withoutalways-on RSs in accordance with aspects of the present disclosure. Theoperations of method 1600 may be implemented by a receiving device, suchas a UE 115, or its components as described herein. For example, theoperations of method 1600 may be performed by a UE RLM manager asdescribed with reference to FIGS. 6 through 9. In some examples, a UE115 may execute a set of codes to control the functional elements of thedevice to perform the functions described below. Additionally oralternatively, the UE 115 may perform aspects of the functions describedbelow using special-purpose hardware.

At 1605 the UE 115 may determine a periodicity of transmission windowsfor an RS. The operations of 1605 may be performed according to themethods described with reference to FIGS. 1 through 5. In certainexamples, aspects of the operations of 1605 may be performed by a DRXperiodicity manager as described with reference to FIGS. 6 through 9.

At 1610 the UE 115 may monitor a radio link quality based at least inpart on an identified DRX periodicity. The operations of 1610 may beperformed according to the methods described with reference to FIGS. 1through 5. In certain examples, aspects of the operations of 1610 may beperformed by a radio link monitoring component as described withreference to FIGS. 6 through 9.

At 1615 the UE 115 may detect a presence of the RS, where the RS isdetected within respective transmission windows. The operations of 1615may be performed according to the methods described with reference toFIGS. 1 through 5. In certain examples, aspects of the operations of1615 may be performed by an RS manager as described with reference toFIGS. 6 through 9.

At 1620 the UE 115 may optionally (e.g., opportunistically) monitor theradio link quality independent of the periodicity of the transmissionwindows based at least in part on the detected presence of the RS. Theoperations of 1620 may be performed according to the methods describedwith reference to FIGS. 1 through 5. In certain examples, aspects of theoperations of 1620 may be performed by a radio link monitoring componentas described with reference to FIGS. 6 through 9.

FIG. 17 shows a flowchart illustrating a method 1700 for RLM withoutalways-on RSs in accordance with aspects of the present disclosure. Theoperations of method 1700 may be implemented by a receiving device, suchas a UE 115, or its components as described herein. For example, theoperations of method 1700 may be performed by a UE RLM manager asdescribed with reference to FIGS. 6 through 9. In some examples, a UE115 may execute a set of codes to control the functional elements of thedevice to perform the functions described below. Additionally oralternatively, the UE 115 may perform aspects of the functions describedbelow using special-purpose hardware.

At 1705 the UE 115 may identify a DRX periodicity for an RS associatedwith RLM procedures. The RS may be associated with a downlink controlchannel. The operations of 1705 may be performed according to themethods described with reference to FIGS. 1 through 5. In certainexamples, aspects of the operations of 1705 may be performed by a DRXperiodicity manager as described with reference to FIGS. 6 through 9.

At 1710 the UE 115 may monitor a radio link quality based at least inpart on the identified DRX periodicity. The operations of 1710 may beperformed according to the methods described with reference to FIGS. 1through 5. In certain examples, aspects of the operations of 1710 may beperformed by a radio link monitoring component as described withreference to FIGS. 6 through 9.

At 1715 the UE 115 may receive the RS according to the DRX periodicity.The operations of 1715 may be performed according to the methodsdescribed with reference to FIGS. 1 through 5. In certain examples,aspects of the operations of 1715 may be performed by an RS manager asdescribed with reference to FIGS. 6 through 9.

At 1720 the UE 115 may decode a downlink control channel. The operationsof 1720 may be performed according to the methods described withreference to FIGS. 1 through 5. In certain examples, aspects of theoperations of 1720 may be performed by a decoder as described withreference to FIGS. 6 through 9.

At 1725 the UE 115 may reset an RLM counter (e.g., an N310 counter)based at least in part on the decoded downlink control channel. Theoperations of 1725 may be performed according to the methods describedwith reference to FIGS. 1 through 5. In certain examples, aspects of theoperations of 1725 may be performed by a RLM counter manager asdescribed with reference to FIGS. 6 through 9.

At 1730 the UE 115 may boost an RLM counter (e.g., an N311 counter)based at least in part on the decoded downlink control channel. Theoperations of 1730 may be performed according to the methods describedwith reference to FIGS. 1 through 5. In certain examples, aspects of theoperations of 1730 may be performed by a RLM counter manager asdescribed with reference to FIGS. 6 through 9.

FIG. 18 shows a flowchart illustrating a method 1800 for RLM withoutalways-on RSs in accordance with aspects of the present disclosure. Theoperations of method 1800 may be implemented by a transmitting device,such as a base station 105, or its components as described herein. Forexample, the operations of method 1800 may be performed by a basestation RLM manager as described with reference to FIGS. 10 through 13.In some examples, a base station 105 may execute a set of codes tocontrol the functional elements of the device to perform the functionsdescribed below. Additionally or alternatively, the base station 105 mayperform aspects of the functions described below using special-purposehardware.

At 1805 the base station 105 may identify an RS associated with RLMprocedures. The RS may be associated with a downlink control channel.The operations of 1805 may be performed according to the methodsdescribed with reference to FIGS. 1 through 5. In certain examples,aspects of the operations of 1805 may be performed by a downlink RScomponent as described with reference to FIGS. 10 through 13.

At 1810 the base station 105 may configure a DRX periodicity for the RS.The operations of 1810 may be performed according to the methodsdescribed with reference to FIGS. 1 through 5. In certain examples,aspects of the operations of 1810 may be performed by a DRXconfiguration manager as described with reference to FIGS. 10 through13.

At 1815 the base station 105 may transmit the RS according to theconfigured DRX periodicity. The operations of 1815 may be performedaccording to the methods described with reference to FIGS. 1 through 5.In certain examples, aspects of the operations of 1815 may be performedby a transmitter as described with reference to FIGS. 10 through 13.

FIG. 19 shows a flowchart illustrating a method 1900 for RLM withoutalways-on RSs in accordance with aspects of the present disclosure. Theoperations of method 1900 may be implemented by a transmitting device,such as a base station 105, or its components as described herein. Forexample, the operations of method 1900 may be performed by a basestation RLM manager as described with reference to FIGS. 10 through 13.In some examples, a base station 105 may execute a set of codes tocontrol the functional elements of the device to perform the functionsdescribed below. Additionally or alternatively, the base station 105 mayperform aspects of the functions described below using special-purposehardware.

At 1905 the base station 105 may identify an RS for a downlink controlchannel, where the RS is associated with RLM procedures. The operationsof 1905 may be performed according to the methods described withreference to FIGS. 1 through 5. In certain examples, aspects of theoperations of 1905 may be performed by a downlink RS component asdescribed with reference to FIGS. 10 through 13.

At 1910 the base station 105 may configure a DRX periodicity for the RS.The operations of 1910 may be performed according to the methodsdescribed with reference to FIGS. 1 through 5. In certain examples,aspects of the operations of 1910 may be performed by a DRXconfiguration manager as described with reference to FIGS. 10 through13.

At 1915 the base station 105 may configure one or more control resourcesets for transmission of the RS associated with the RLM procedures,where the one or more control resource sets comprise at least resourcesassociated with a common control channel or resources associated with aUE-specific control channel. The operations of 1915 may be performedaccording to the methods described with reference to FIGS. 1 through 5.In certain examples, aspects of the operations of 1915 may be performedby a control resource set manager as described with reference to FIGS.10 through 13.

At 1920 the base station 105 may transmit the RS according to theconfigured DRX periodicity. The operations of 1920 may be performedaccording to the methods described with reference to FIGS. 1 through 5.In certain examples, aspects of the operations of 1920 may be performedby a transmitter as described with reference to FIGS. 10 through 13.

It should be noted that the methods described above describe possibleimplementations, and that the operations and the steps may be rearrangedor otherwise modified and that other implementations are possible.Further, aspects from two or more of the methods may be combined.

Techniques described herein may be used for various wirelesscommunications systems such as code division multiple access (CDMA),time division multiple access (TDMA), frequency division multiple access(FDMA), orthogonal frequency division multiple access (OFDMA), singlecarrier frequency division multiple access (SC-FDMA), and other systems.The terms “system” and “network” are often used interchangeably. A CDMAsystem may implement a radio technology such as CDMA2000, UniversalTerrestrial Radio Access (UTRA), etc. CDMA2000 covers IS-2000, IS-95,and IS-856 standards. IS-2000 Releases may be commonly referred to asCDMA2000 1×, 1×, etc. IS-856 (TIA-856) is commonly referred to asCDMA2000 1×EV-DO, High Rate Packet Data (HRPD), etc. UTRA includesWideband CDMA (WCDMA) and other variants of CDMA. A TDMA system mayimplement a radio technology such as Global System for MobileCommunications (GSM).

An OFDMA system may implement a radio technology such as Ultra MobileBroadband (UMB), Evolved UTRA (E-UTRA), Institute of Electrical andElectronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE802.20, Flash-OFDM, etc. UTRA and E-UTRA are part of Universal MobileTelecommunications System (UMTS). LTE and LTE-A are releases of UMTSthat use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, NR, and GSM aredescribed in documents from the organization named “3rd GenerationPartnership Project” (3GPP). CDMA2000 and UMB are described in documentsfrom an organization named “3rd Generation Partnership Project 2”(3GPP2). The techniques described herein may be used for the systems andradio technologies mentioned above as well as other systems and radiotechnologies. While aspects of an LTE or an NR system may be describedfor purposes of example, and LTE or NR terminology may be used in muchof the description, the techniques described herein are applicablebeyond LTE or NR applications.

In LTE/LTE-A networks, including such networks described herein, theterm evolved node B (eNB) may be generally used to describe the basestations. The wireless communications system or systems described hereinmay include a heterogeneous LTE/LTE-A or NR network in which differenttypes of eNBs provide coverage for various geographical regions. Forexample, each eNB, next generation NodeB (gNB), or base station mayprovide communication coverage for a macro cell, a small cell, or othertypes of cell. The term “cell” may be used to describe a base station, acarrier or component carrier associated with a base station, or acoverage area (e.g., sector, etc.) of a carrier or base station,depending on context.

Base stations may include or may be referred to by those skilled in theart as a base transceiver station, a radio base station, an accesspoint, a radio transceiver, a NodeB, eNodeB (eNB), gNB, Home NodeB, aHome eNodeB, or some other suitable terminology. The geographic coveragearea for a base station may be divided into sectors making up only aportion of the coverage area. The wireless communications system orsystems described herein may include base stations of different types(e.g., macro or small cell base stations). The UEs described herein maybe able to communicate with various types of base stations and networkequipment including macro eNBs, small cell eNBs, gNBs, relay basestations, and the like. There may be overlapping geographic coverageareas for different technologies.

A macro cell generally covers a relatively large geographic area (e.g.,several kilometers in radius) and may allow unrestricted access by UEswith service subscriptions with the network provider. A small cell is alower-powered base station, as compared with a macro cell, that mayoperate in the same or different (e.g., licensed, unlicensed, etc.)frequency bands as macro cells. Small cells may include pico cells,femto cells, and micro cells according to various examples. A pico cell,for example, may cover a small geographic area and may allowunrestricted access by UEs with service subscriptions with the networkprovider. A femto cell may also cover a small geographic area (e.g., ahome) and may provide restricted access by UEs having an associationwith the femto cell (e.g., UEs in a closed subscriber group (CSG), UEsfor users in the home, and the like). An eNB for a macro cell may bereferred to as a macro eNB. An eNB for a small cell may be referred toas a small cell eNB, a pico eNB, a femto eNB, or a home eNB. An eNB maysupport one or multiple (e.g., two, three, four, and the like) cells(e.g., component carriers).

The wireless communications system or systems described herein maysupport synchronous or asynchronous operation. For synchronousoperation, the base stations may have similar frame timing, andtransmissions from different base stations may be approximately alignedin time. For asynchronous operation, the base stations may havedifferent frame timing, and transmissions from different base stationsmay not be aligned in time. The techniques described herein may be usedfor either synchronous or asynchronous operations.

The downlink transmissions described herein may also be called forwardlink transmissions while the uplink transmissions may also be calledreverse link transmissions. Each communication link describedherein—including, for example, wireless communications system 100 and200 of FIGS. 1 and 2—may include one or more carriers, where eachcarrier may be a signal made up of multiple sub-carriers (e.g., waveformsignals of different frequencies).

The description set forth herein, in connection with the appendeddrawings, describes example configurations and does not represent allthe examples that may be implemented or that are within the scope of theclaims. The term “exemplary” used herein means “serving as an example,instance, or illustration,” and not “preferred” or “advantageous overother examples.” The detailed description includes specific details forthe purpose of providing an understanding of the described techniques.These techniques, however, may be practiced without these specificdetails. In some instances, well-known structures and devices are shownin block diagram form in order to avoid obscuring the concepts of thedescribed examples.

In the appended figures, similar components or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If just the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label.

Information and signals described herein may be represented using any ofa variety of different technologies and techniques. For example, data,instructions, commands, information, signals, bits, symbols, and chipsthat may be referenced throughout the above description may berepresented by voltages, currents, electromagnetic waves, magneticfields or particles, optical fields or particles, or any combinationthereof.

The various illustrative blocks and modules described in connection withthe disclosure herein may be implemented or performed with ageneral-purpose processor, a DSP, an ASIC, an FPGA or other programmablelogic device, discrete gate or transistor logic, discrete hardwarecomponents, or any combination thereof designed to perform the functionsdescribed herein. A general-purpose processor may be a microprocessor,but in the alternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices (e.g., a combinationof a DSP and a microprocessor, multiple microprocessors, one or moremicroprocessors in conjunction with a DSP core, or any other suchconfiguration).

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on acomputer-readable medium. Other examples and implementations are withinthe scope of the disclosure and appended claims. For example, due to thenature of software, functions described above can be implemented usingsoftware executed by a processor, hardware, firmware, hardwiring, orcombinations of any of these. Features implementing functions may alsobe physically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations. Also, as used herein, including in the claims, “or” as usedin a list of items (for example, a list of items prefaced by a phrasesuch as “at least one of” or “one or more of”) indicates an inclusivelist such that, for example, a list of at least one of A, B, or C meansA or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also, asused herein, the phrase “based on” shall not be construed as a referenceto a closed set of conditions. For example, an exemplary step that isdescribed as “based on condition A” may be based on both a condition Aand a condition B without departing from the scope of the presentdisclosure. In other words, as used herein, the phrase “based on” shallbe construed in the same manner as the phrase “based at least in parton.”

Computer-readable media includes both non-transitory computer storagemedia and communication media including any medium that facilitatestransfer of a computer program from one place to another. Anon-transitory storage medium may be any available medium that can beaccessed by a general purpose or special purpose computer. By way ofexample, and not limitation, non-transitory computer-readable media maycomprise RAM, ROM, electrically erasable programmable read only memory(EEPROM), compact disk (CD) ROM or other optical disk storage, magneticdisk storage or other magnetic storage devices, or any othernon-transitory medium that can be used to carry or store desired programcode means in the form of instructions or data structures and that canbe accessed by a general-purpose or special-purpose computer, or ageneral-purpose or special-purpose processor. Also, any connection isproperly termed a computer-readable medium. For example, if the softwareis transmitted from a website, server, or other remote source using acoaxial cable, fiber optic cable, twisted pair, digital subscriber line(DSL), or wireless technologies such as infrared, radio, and microwave,then the coaxial cable, fiber optic cable, twisted pair, DSL, orwireless technologies such as infrared, radio, and microwave areincluded in the definition of medium. Disk and disc, as used herein,include CD, laser disc, optical disc, digital versatile disc (DVD),floppy disk and Blu-ray disc where disks usually reproduce datamagnetically, while discs reproduce data optically with lasers.Combinations of the above are also included within the scope ofcomputer-readable media.

The description herein is provided to enable a person skilled in the artto make or use the disclosure. Various modifications to the disclosurewill be readily apparent to those skilled in the art, and the genericprinciples defined herein may be applied to other variations withoutdeparting from the scope of the disclosure. Thus, the disclosure is notlimited to the examples and designs described herein, but is to beaccorded the broadest scope consistent with the principles and novelfeatures disclosed herein.

What is claimed is:
 1. A method for wireless communication at a userequipment (UE), comprising: identifying a periodicity of transmissionwindows for a reference signal (RS) used for radio link monitoring (RLM)procedures, wherein the RS is received within respective transmissionwindows; receiving the RS according to the periodicity of thetransmission windows; selecting the RS within a particular transmissionwindow for the RLM procedures based at least in part on one or moresignal-to-noise ratios (SNRs) of discrete transmissions of one or moreRSs including the RS within the transmission window; and monitoring theradio link quality based at least in part on the selected RS and on theidentified periodicity of transmission windows for the RS.
 2. The methodof claim 1, further comprising: determining a periodicity of thediscrete transmissions of the RS.
 3. The method of claim 2, furthercomprising: monitoring the radio link quality independent of theperiodicity of the discrete transmissions of the RS based at least inpart on a detected presence of the RS.
 4. The method of claim 2, whereinthe periodicity of the discrete transmissions of the RS is independentof reception of control channels.
 5. The method of claim 1, furthercomprising: detecting a presence of the RS outside of the transmissionwindows for the RS; and monitoring the radio link quality outside of thetransmission windows based at least in part on the detected presence ofthe RS.
 6. The method of claim 1, wherein each of the respectivetransmission windows comprises one or more transmission time intervals(TTIs), and wherein the RS is included within at least one TTI of theone or more TTIs.
 7. The method of claim 1, further comprising:receiving an indication of the periodicity or of a length of therespective transmission windows via radio resource control (RRC)signaling, system information broadcast signaling, or a combinationthereof.
 8. The method of claim 1, further comprising: identifying oneor more control resource sets associated with receiving the RSassociated with the RLM procedures.
 9. The method of claim 8, whereinthe one or more control resource sets comprise at least resourcesassociated with a common control channel or resources associated with aUE-specific control channel.
 10. The method of claim 1, furthercomprising: identifying a first control resource set associated withreceiving the RS; identifying a second control resource set associatedwith receiving the RS; and using at least the first control resourceset, the second control resource set, or a combination thereof for theRLM procedures.
 11. The method of claim 1, wherein the RLM proceduresare associated with a downlink control channel, the method furthercomprising: decoding the downlink control channel; and resetting orboosting an RLM counter based at least in part on the decoded downlinkcontrol channel.
 12. The method of claim 11, wherein boosting the RLMcounter comprises: identifying a type of control channel resources or anaggregation level associated with the downlink control channel; andboosting the RLM counter based at least in part on the identified typeof control channel resources or aggregation level.
 13. A method forwireless communication at a user equipment (UE), comprising: identifyinga periodicity of transmission windows for a reference signal (RS) usedfor radio link monitoring (RLM) procedures, wherein the RS is receivedwithin respective transmission windows; receiving the RS according tothe periodicity of transmission windows; selecting the RS within aparticular transmission time interval (TTI) for the RLM procedures basedat least in part on one or more signal-to-noise ratios (SNRs) ofdiscrete transmissions of one or more RSs, including the RS, within oneor more TTIs within the respective transmission windows; and monitoringa radio link quality based at least in part on the selected RS.
 14. Anapparatus for wireless communication, in a system comprising: aprocessor; memory in electronic communication with the processor; andinstructions stored in the memory and operable, when executed by theprocessor, to cause the apparatus to: identify a periodicity oftransmission windows for a reference signal (RS) used for radio linkmonitoring (RLM) procedures, wherein the RS is received withinrespective transmission windows; receive the RS according to theperiodicity of the transmission windows; select the RS within aparticular transmission window for the RLM procedures based at least inpart on one or more signal-to-noise ratios (SNRs) of discretetransmissions of one or more RSs, including the RS, within thetransmission window; and monitor the radio link quality based at leastin part on the selected RS and on the identified periodicity oftransmission windows for the RS.
 15. The apparatus of claim 14, whereinthe instructions are executable by the processor to cause the apparatusto: determine a periodicity of the discrete transmissions of the RS. 16.The apparatus of claim 15, wherein the instructions are executable bythe processor to cause the apparatus to: detect a presence of the RSoutside of the transmission windows for the RS; and monitor the radiolink quality outside of the discrete transmissions of the RS based atleast in part on the detected presence of the RS.
 17. The apparatus ofclaim 14, wherein each of the respective transmission windows comprisesone or more transmission time intervals (TTIs), and wherein the RS isincluded within at least one TTI of the one or more TTIs.
 18. Theapparatus of claim 14, wherein the instructions are executable by theprocessor to cause the apparatus to: receive an indication of theperiodicity or of a length of the respective transmission windows viaradio resource control (RRC) signaling, system information broadcastsignaling, or a combination thereof.
 19. The apparatus of claim 14,wherein the periodicity of the discrete transmissions of the RS isindependent of reception of control channels.
 20. The apparatus of claim14, wherein the instructions are executable by the processor to causethe apparatus to: identify one or more control resource sets associatedwith receiving the RS associated with the RLM procedures.
 21. Theapparatus of claim 20, wherein the one or more control resource setscomprise at least resources associated with a common control channel orresources associated with a UE-specific control channel.
 22. Theapparatus of claim 14, wherein the instructions are executable by theprocessor to cause the apparatus to: identify a first control resourceset associated with receiving the RS; identify a second control resourceset associated with receiving the RS; and use at least the first controlresource set, the second control resource set, or a combination thereoffor the RLM procedures.
 23. The apparatus of claim 14, wherein the RLMprocedures are associated with a downlink control channel and theinstructions are executable by the processor to cause the apparatus to:decode the downlink control channel; and reset or boosting an RLMcounter based at least in part on the decoded downlink control channel.24. The apparatus of claim 23, wherein the instructions executable bythe processor to cause the apparatus to boost the RLM counter compriseinstructions executable by the processor to: identify a type of controlchannel resources or an aggregation level associated with the downlinkcontrol channel; and boost the RLM counter based at least in part on theidentified type of control channel resources or aggregation level. 25.An apparatus for wireless communication, in a system comprising: aprocessor; memory in electronic communication with the processor; andinstructions stored in the memory and operable, when executed by theprocessor, to cause the apparatus to: identify a periodicity oftransmission windows for a reference signal (RS) used for radio linkmonitoring (RLM) procedures, wherein the RS is received withinrespective transmission windows; receive the RS according to theperiodicity of transmission windows; select the RS within a particulartransmission time interval (TTI) for the RLM procedures based at leastin part on one or more signal-to-noise ratios (SNRs) of discretetransmissions of one or more RSs, including the RS, within one or moreTTIs within the respective transmission windows; and monitor a radiolink quality based at least in part on the selected RS and on theidentified periodicity of transmission windows.